SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4300b15d579f06b0310917e66c9a969ab9a9c0b35bb7ae3f6ae376537d754074' 
  AND token = '7sejMwJNv1zd0AMwPyyhT98uraHxyUB1Dp0J0RB3wFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}